如何从UIBezierPath生成CGPoint-Array（沿给定路径触摸滑动对象） [英] How to generate CGPoint-Array out of UIBezierPath (to touch-slide object along given path)

问题描述

我有一个UIBezierPath（曲线像'8'，只有4个点），我需要制作一些CGPoint-Array。有任何想法吗？ thanx！

I have a UIBezierPath (curved like an '8', with only 4 points in it) and I need to make some kind of CGPoint-Array out of it. Any ideas? thanx!

编辑：

我的bezier初始化就像那样

I have my bezier initlialized like that

-(void) initBezier
{
    theBezierPath = [UIBezierPath bezierPath];    
    [theBezierPath moveToPoint:P(211.00, 31.00)];
    [theBezierPath addCurveToPoint:P(870.00, 191.00) controlPoint1:P(432.00, -11.00) controlPoint2:P(593.00, 209.00)];
    [theBezierPath addCurveToPoint:P(731.00, 28.00) controlPoint1:P(1061.95, 178.53) controlPoint2:P(944.69, 5.78)];
    [theBezierPath addCurveToPoint:P(189.00, 190.00) controlPoint1:P(529.00, 49.00) controlPoint2:P(450.00, 189.00)];
    [theBezierPath addCurveToPoint:P(211.00, 31.00) controlPoint1:P(-33.01, 190.85) controlPoint2:P(71.00, 37.00)];
}

我用

anim = [CAKeyframeAnimation animationWithKeyPath:@"emitterPosition"];
anim.path = theBezierPath.CGPath;
anim.calculationMode = kCAAnimationCubicPaced;
anim.repeatCount = HUGE_VALF;
anim.duration = tme;

我想逐个像素地（通过触摸位置）为路径上的对象设置动画。我希望对象将触摸的给定坐标捕捉到曲线上最近的点，以便沿着路径触摸滑动对象。

I want to animate the object on the path pixel by pixel (via touch-position). I want the object to "snap" a given coordinate of a touch to the nearest point on the curve so it touch-slides the object along the path.

推荐答案

使用 CGPathApply（）函数迭代路径中的所有元素。作为参数之一，您必须指定一个函数的指针，然后为每个路径元素调用该函数。路径元素数据结构（类型 CGPathElement ）然后包含描述它的点。

Use the CGPathApply() function to iterate over all elements in a path. As one of the arguments, you have to specify a pointer to a function that will then be called for each path element. The path element data structure (of type CGPathElement) then contains the point(s) that describe it.

使用 NSValue 作为将点添加到 NSMutableArray 的包装器。

Use NSValue as a wrapper to add the points to an NSMutableArray.

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